Weed and grass trimmers using a flailing line for cutting purposes are widely used for many different kinds of trimming, such as around obstacles and edging, where the plane occupied by the rotating flail is differently oriented, sometimes horizontally, sometimes vertically, and sometimes in between these two positions.
One conventional trimmer is comprised of an engine or motor mounted on the outboard end of a handle shaft, and a drive head at the other end of the shaft. The flailing line is driven by a cable that passes through the handle shaft from the motor to the drive head. A grip on the handle shaft and an outwardly extending handle permit the operator to manuever the plane of the rotating cutting line by tilting the drive head at whatever angle is necessary. In other conventional devices, both the motor and the drive head are located at the distal end of the handle shaft.
A difficulty in the use of such trimmers is that the weight of the engine makes maneuvering and tilting at various angles tiring particularly when the engine and the drive head are at opposite ends of the device. The engine is usually mounted and balanced for use in one position relative to the handle, and a positive torque must be applied to tilt the assembly. Also, when an internal combustion engine is used, it may not operate properly if tilted at excessively steep angles. The tilting can affect the flow of fuel which will disturb engine operation or even cause it to stop. It is advantageous for the internal combustion engine to remain in one suitable orientation when the drive head is tilted at various angles relative to the engine to tilt the cutting line. This also reduces operator fatigue. When the motor is carried on the head (then it is usually an electric motor), it is still useful to be able to change the head orientation relative to the handle so the user can have the most effort-free grip on the assembly.
Therefore it is one object of the present invention to provide a trimmer with a drive head that is tiltably adjustable relative to a handle, and optionally also relative to an engine or motor on the handle end.
Another object of the invention is to provide a trimmer having a two-part handle shaft, with one part being rotatable relative to the other, and the other part fixed relative to a handle.